Insulator construction for circuit breakers



July 30, 1963 Y. PELENC 3,099,721

INSULATOR CONSTRUCTION FOR CIRCUIT BREAKERS Filed Feb. 24, 1959 IN VENTOR Yl/ES PELENG ATTORNEY United States Patent 3,099,721 INSULATOR CONSTRUCTION FOR CIRCUIT BREAKERS Yves Pelenc, La Buisserate-Saint-Martin le-Vinoux, Isere, France Filed Feb. 24, 1959, Ser. No. 795,122 1 Claim. (Cl. 200-48) This invention relates generally to the type of circuit breaker having an arc extinction chamber operatively associated with a fixed contact, and a movable contact supported on an arm or blade pivoting around a center to engage against the fixed contact to open and close a circuit.

Circuit breakers of modern type usually consist of two insulators for each pole, one supporting the fixed contact and the arc extinction chamber the other supporting the movable contact. The insulators are mounted on a frame which may be used as a housing to enclose the control assembly for the moving parts. Prior art insulators are generally fixed in horizontal position, and the distance between them is determined by the intended service for the circuit breaker and must be great enough to provide sufficient insulation to prevent a flashover between the contacts. The length of the insulators is a function of the rated voltage of the circuit breaker, and of course, the overall dimensions of the apparatus, and the amount of cantilever of the insulators depends on this length, the other dimensions of the insulator, cantilever-supporting at its free end the arc extinction chamber, being a function of the weight of said chamber.

In an attempt to reduce the overall dimensions, others have provided supporting insulators having parallel axes and forming an angle with the horizontal plane. As will later be more fully explained below, the instant invention provides a circuit breaker which yields minimum overall dimensions for a given voltage and also has a symmetrical appearance which is pleasing to the eye.

It is accordingly a broad object of this invention to improve on the circuit breakers now in use.

It is another and more specific object of this invention to provide a circuit breaker having minimum overall dimensions for a given voltage.

It is a yet further object of this invention to provide a circuit breaker of the type having a pair of contacts respectively carried on cantilever insulators and an arc extinction chamber cantilever-supported at the free end of one of the insulators and wherein the longitudinal axes of the insulators are divergent in a direction away from the insulator supporting structure.

Referring now to the drawings, wherein:

FIGURE 1 is a side elevation of a circuit breaker embodying the instant invention, and

FIGURE 2 is a fragmentary perspective view of a portion of the circuit breaker of FIGURE 1 showing the frame and a portion of the insulators.

summarily stated, the invention consists of a circuit interrupter having a pair of spaced circuit terminals with a contact fixed to each terminal, one contact being pivoted to its respective terminal for motion toward and away from the other contact to close and open a circuit; a pair of diverging insulators are provided to carry the respective contacts and a frame supports the assembly and is adapted to be secured to a vertical supporting surface, such frame being triangular in section to house a control assembly and having formed on its outer face a pair of planar areas respectively normal to the respective insulators. The diverging insulators thus extend between a respective planar area and a respective contact.

In the drawing, reference character 1 designates generally the frame for the \circuit breaker which is triangular in section to provide a volume for housing a control as- 3,099,721 Patented July 30, 1963 sembly. The forward face of the frame, best seen in FIGURE 2, has a pair of planar areas 2 and 3 having a common line of intersection. The rearward face of the frame is adapted to be secured to a substantially vertical supporting wall. A pair of insulators 4 and 5 are supported by the frame 1 and have their respective longitudinal axes disposed in a common vertical plane and respectively diverging in a direction away from the frame, substantially as there shown. In the illustrated embodiment, a line passing through the common axis of intersection of the planar areas will cross the intersection of the axes of the insulators when extended behind the frame. As there shown, the respective axes of the divergent insulators are normal to the planar areas 2 and 3. This, however, is intended to be illustrative of the principle involved and not a limitation on the invention.

It is advantageous to IChOOSC the angle formed between the axes of the insulator and the horizontal plane substantially equal to 30, because it is thereby possible to obtain within a very reduced space the maximum distance between the live parts of the circuit-breaker and ground as well as between the live parts inter se.

This arrangement allows the reduction of the length of the insulator to the minimum value compatible with the prescribed flashover distances while providing an opening angle between the two insulators of one pole smaller than and an opening angle smaller than 90 between the open and closed positions of the blade carrying the movable contact, which feature is most important from the mechanical point of view and facilitates the execution of the actuating mechanism.

Another advantage offered by the use of the angle of 30 between the insulator axes and the horizontal plane is the fact that the oblique faces of the frame which carry the insulators and the frame can be more easily and cheaply formed by a manufacturing process than by the process which would be necessary if this angle were larger.

Insulator 5 carries at its distal end a metal cap 6 having circuit terminal 7 secured thereto. A movable blade 8 is pivotally mounted by pin 10 at one end thereof to cap 6 and has movable contact 9 at the other end. A rod 11 extends between the blade 8 and the control assembly (not shown) within the housing 1. An auxiliary blade 12 is pivoted to blade 8 as by pin 13 for use in controlling the are when the circuit is interrupted. This operation will be readily understood by referring to Patent No. 2,815,418 to Latour, which is hereby incorporated by reference.

The fixed contact 18 for cooperation with movable contact 9 is housed within arc extinction chamber 14, both being supported by insulator 4. A second circuit terminal 15 is also supported by insulator 4 substantially as shown.

As seen in FIGURE 1, the arc extinction chamber 14 has a form generally parallelepipedic, the parallelepiped having a corner removed to form a face. The insulator 4 engages against the face and supports the chamber.

It will be understood that insulators 4 and 5 may be elliptical in cross section, as illustrated in application Serial No. 598,126 filed July 16, 1956, by Latour et al, now Patent No. 2,875,305.

As previously discussed, the longitudinal axes of insulators 4 and 5 respectively form an angle of 30 with the horizontal plane; therefore, the insulating distance designated by a corresponding to the length of the insulators is maintained:

(1) Between the live parts of the arc extinction chamber and the mounting wall (ground),

(2) Between the fixed and movable contacts when the circuit breaker is open,

(3) Between the frame (ground) and the movable con- 3 tact when the circuit breaker is closed (shown in broken lines in FIGURE 1).

From the foregoing it will be seen that I have provided a circuit breaker of minimum overall dimension for a given rated voltage, thus saving material for the enclosure thereof, and which is at once pleasing in appearance and symmetrical in design.

It should be understood that this invention is not limited to specific details of construction and arrangements thereof herein illustrated and that changes and modifications may occur to those skilled in the art without departing from the spirit of the invention.

I claim:

An air break circuit breaker comprising a base housing, a pair of stand-off insulators carried by said housing and extending therefrom in directions inclined respectively above and below the horizontal plane midway between said insulators, the axes of said insulators lying substantially in a common vertical plane; respective fixed and moving cooperating contact elements carried by the outer ends of the respective upwardly and downwardly extending insulators and positioned to define a circuit-breaker region lying vertically between said outer ends; an arcextinction chamber cantilevered at the outer end of said upwardly extending insulator and surrounding said fixed contact element; the upwardly extending one of said insulators having a terminal face substantially perpendicular to the axis of said insulator; said arc-extinction chamber having at least one corner schamfered to parallel said terminal face, and means connecting said chamfered corner surface to the said terminal face; said one upwardly extending insulator constituting the sole support for said chamber.

References Cited in the file of this patent UNITED STATES PATENTS 2,250,216 Biermanns July 22, 1941 2,717,287 Sihler et al. Sept. 6, 1955 2,875,305 Latour et al. Feb. 24, 1959 FOREIGN PATENTS 733,778 France Oct. 11, 1932 903,172 France Sept. 26, 1945 1,129,604 France Jan. 23, 1957 1,187,019 France Sept. 4, 1959 

